THE transportation of optical images has been carried out hitherto with the aid of lenses or mirrors or both. As with all optical systems, aberrations are introduced and the parts have to be aligned ...

Life is ubiquitous on Earth and appears in a diversity of forms. But what characteristics do organisms have? What makes them alive? This activity explores that question. In the first part of the ...

The Trump administration has merged state authority with private interests, treating political power as a monetizable ...